JP3313177B2 - Cylindrical plate cylinder for stencil printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical plate cylinder for a stencil printing machine , and more particularly to a cylindrical plate cylinder for a stencil printing machine suitable for controlling an ink transfer amount of a rotary stencil printing machine.

[0002]

2. Description of the Related Art A stencil printing method has an advantage that a large amount of printed matter can be obtained at a lower cost than other printing methods. It has been known. The rotary stencil printing machine has a porous cylindrical plate cylinder which is provided with stencil paper on the outer peripheral surface, is supplied with ink from the inner peripheral surface, and rotates around its own axis.
The cylindrical plate cylinder includes a generally cylindrical supporting cylinder having a large number of small holes constituting an innermost layer thereof, and a screen layer wound around the outer peripheral surface of the supporting cylinder. There are known those in which a screen layer is wound directly between a pair of flanges without a supporting cylinder.

[0003] In order to improve the transferability of the ink, a screen layer made of polyester fibers having a fine mesh structure, a screen made of a low-mesh stainless steel screen and a screen made of a high-mesh tetron fabric or the like are used as the screen layer. multiple screens layer provided in this order is employed (JP-B 63-59393, JP-a No. 3 -25
No. 4986). However, as in the former, when the screen layer of the fine mesh is provided directly on the support cylinder, the screen is easily rubbed, and there is a problem that the small holes of the support cylinder appear as shadows on the printed image. In the case where the supporting cylinder is not provided, the ink supply roller built into the cylindrical plate cylinder comes into direct contact with the screen, so that the degree of rubbing of the screen is large, and uniform ink cannot be supplied. There is a problem in that the rigidity is insufficient due to rubbing, so that bending is likely to occur during a printing operation, and that the pressure distribution at the time of printing becomes uneven because the surface state of the screen is not smooth. In the latter case, two types of screens are used, so that the cost is increased and there is an inconvenience that ink is formed between the two layers.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cylindrical plate cylinder for a stencil printing machine which solves the above-mentioned problems of the prior art and can improve ink transferability and printability at low cost. Is to do.

[0005]

According to the first aspect of the present invention,
Ming, stencil sheet is mounted on the outer peripheral surface, the inner peripheral surface ink is supplied from, and in a stencil printing machine cylindrical printing drum which rotates around a central axis of itself, woven der the ink-permeable
Therefore, polyethylene terephthalate as a high melting point component,
Sheath-core type or side than this lower component melting point was low melting point component - by - woven and have use of composite fibers of side-type,
A woven fabric having a fiber intersection fixed by softening or hot-melting the low melting point component by thermocompression bonding is brought into contact with the inner surface of the stencil paper.
It has urchin disposed about stencil printing machine cylinder plate cylinder, characterized in.

The stencil printing machine cylindrical plate cylinder of the present invention has
Woven woven cloth (hereinafter sometimes referred to as screen)
Is a stencil attached to the outer peripheral surface of a cylindrical plate cylinder during printing
It is arranged so as to be in contact with the inner surface of the base paper. The above cylinder
The above woven fabric placed on the plate cylinder is called the screen layer
There is. The screen used in the present invention is obtained by weaving a sheath-core type or side-by-side type composite fiber composed of a low-melting component and a high-melting component using a part or all thereof,
It is obtained by softening and deforming the low melting point component or fixing the fiber intersection by heat melting.

[0007] As the high melting point component constituting the composite fiber ,
Polyethylene terephthalate (polyester)
Is used. Polyethylene terephthalate
Low affinity with the ink to improve ink passage.
Can be. As low melting point component, lower than high melting point component
It has a melting point, has good bondability with the high melting point component, and is not particularly limited as long as it can be easily softened or melted at the time of thermocompression bonding to fix the fiber intersection, for example, polyester copolymer, polypropylene, A thermoplastic resin such as a polypropylene-ethylene copolymer is exemplified. In particular, a copolymerized polyester obtained by copolymerizing other monomers and reaction components such as polyalkylene glycols, dicarboxylic acids, and low molecular weight glycols during polymerization is preferably used . In the case of a sheath- core type composite fiber, a low melting point component is used as the sheath component.

[0008] The content of the low melting point component in the conjugate fiber is such that the component is softened or melted by thermocompression bonding so that the fiber intersection can be bonded and fixed with a sufficient adhesive strength, and the pores of the screen are softened or melted by heat. It is sufficient that the amount is not crushed, and is usually 5 to 70% of the fiber cross-sectional area, preferably 10 to 70%.
The range is 50%. The cross-sectional shape of the conjugate fiber may be circular or deformed.

The sheath-core type or side-by-side type conjugate fiber is obtained by a conventional melt spinning method using a known spinning nozzle for conjugate, and the conjugate fiber (filament) is partially or wholly used. To obtain the screen used in the present invention. The screen may be composed only of the composite fiber, but may be a composite fiber only for a part of the fiber, for example, the warp or weft, or every other warp or weft. Etc. may be used. Fibers used other than composite fibers include:
For example, ordinary fibers made of the above-mentioned polyester having a high melting point can be used.

[0010] The woven screen is bonded or fixed at the fiber intersection by softening or hot-melting the low melting point component of the composite fiber by thermocompression bonding means such as a nip roll. The temperature and pressure of the thermocompression bonding are appropriately determined according to the material of the screen.For example, in the case of a cloth made of a polyester composite yarn using a copolymerized polyester as a low melting point component, a metal roll heated to 120 ° C. It can be thermocompressed by passing between silicone rubber rolls at a nip pressure of 1.8 kg / cm ² . The aperture of the screen after the thermocompression bonding is not particularly limited, but is preferably in the range of 70 to 400 mesh from the viewpoint of ink transferability and the thickness is preferably in the range of 40 to 200 μm. The screen layer is usually preferably a single layer, but may be a plurality of layers.

In the present invention, the screen layer of the cylindrical plate cylinder for a stencil printing machine is a screen which is woven using a part or all of the conjugate fiber, and thermocompression-bonded to join and fix the fiber intersections. Thereby, the rigidity of the screen is improved, and the occurrence of rubbing and bending of the screen at the time of printing can be prevented, and the thickness of the screen can be reduced uniformly to improve the smoothness of the screen surface.
Regardless of the presence or absence of the support cylinder, it is easy to control the amount of ink transfer, improving not only the printing workability but also the printing image quality, and it is not necessary to use two types of screen layers.
Ku, lower costs can be achieved.

FIG. 1 is a schematic structural view of a rotary stencil printing apparatus provided with a cylindrical plate cylinder having a supporting cylindrical body according to the present invention;
FIG. 2 is an enlarged plan view showing a porous state of each ink passage layer constituting the cylindrical plate cylinder of FIG. In FIG. 1, a cylindrical plate cylinder 1 includes a support cylinder 2 having a number of small holes constituting an innermost layer, and a screen layer 3 wound around the outer periphery of the support cylinder 2. A stencil sheet 4 is mounted on the outer periphery of the stencil. The support cylinder 2 and the screen layer 3 have a large number of ink-permeable small holes shown in FIGS. 2 (A) and 2 (B). The small holes of the support cylinder 2 are usually about 20 to 60 mesh. A squeegee roller 10 slidably in contact with the inner peripheral surface of the support cylinder 2 and rotationally driven in the same direction. Doctor rod 1
1 are installed, and ink is supplied to the ink reservoir 13 between them. The ink in the ink reservoir 13 is transferred from the squeegee roller 10 to the printing paper 5 via the support cylinder 2, the screen layer 3 and the stencil 4. The printing paper 5 is conveyed while being selectively pressed against the outer peripheral surface of the plate cylinder 1 by a press roller 14 that moves up and down.

[0013]

The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Example 1 Polyester composite fiber having a sheath-core structure (monofilament)
A screen made of NBC (manufactured by NBC Industries, Inc., mesh 200, thickness 75 μm) was nip-pressed 1.8 k between a metal roll and a silicone rubber roll heated to 120 ° C.
g / cm ² . The screen was mounted on a plate cylinder of an integrated stencil printing machine (RC-115) manufactured by Riso Kagaku Kogyo Co., Ltd. to perform stencil printing. A good image was obtained, and the screen was rubbed during the printing operation. No problem such as bending occurred.

Example 2 A side-by-side type polyester composite fiber obtained by subjecting a low melting point component (copolyester) and a high melting point component (homopolyester) to composite spinning at a ratio of 50/50 (weight ratio) was used. A screen ( 200 mesh, 75 μm in thickness) using normal polyester fiber for warp and weft
m) was prepared. After the screen was thermocompressed under the same conditions as in Example 1, stencil printing was performed. However, good images were obtained, and no problems such as scratching and bending of the screen occurred during the printing operation. .

Comparative Example 1 A screen made of polypropylene fiber (manufactured by NBC Industries, trade name: PP200, mesh size: 200 mesh, thickness: 1)
(60 μm) was subjected to a heat treatment under the same conditions as in Example 1, and this was similarly mounted on a drum to perform stencil printing. Although the stiffness of the screen was improved by the heat treatment, the entire fiber was melted by heat, so that the porosity of the screen was reduced, the image density of the printed matter was extremely low, and good images could not be obtained.

Comparative Example 2 The screen knitted with the sheath-core structure fiber used in Example 1 was mounted on a plate cylinder and heat-printed in the same manner as in Example 1 without heat treatment. The inside of the screen was rubbed or bent, and an uneven portion was generated in the image.

[0017]

According to the present invention, polyester terephthalate is used as a screen layer of a cylindrical plate cylinder for a stencil printing machine .
Woven using a part or all of a composite fiber having a high melting point component, and using a screen in which the fiber intersections are joined by thermocompression bonding to improve the rigidity of the screen,
Prevents scratches and warpage during printing, reduces the screen thickness uniformly, improves the smoothness of the screen surface, makes it easy to control the amount of ink transfer, and provides only printing workability. The image quality of the printed matter can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a rotary stencil printing machine provided with a cylindrical plate cylinder according to the present invention.

FIG. 2 is an enlarged plan view showing a porous state of each ink passage layer constituting the cylindrical plate cylinder of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cylindrical plate cylinder, 2 ... Support cylinder, 3 ... Screen layer,
4: stencil paper, 5: printing paper, 10: squeegee roller,
11 doctor rod, 12 gap, 13 ink reservoir, 14 press roller .

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-254986 (JP, A) JP-A-61-282467 (JP, A) JP-A-2-80640 (JP, A) 56787 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41L 13/04

Claims (1)

(57) [Claims] 1. A stencil sheet is mounted on the outer peripheral surface, the inner peripheral surface ink is supplied from, and in a stencil printing machine cylindrical printing drum which rotates around its central axis, the ink-permeable
Woven fabric made of polyethylene terephthalate with high melting point
Min and, sheath-core type or side was from the lower component melting point which the low melting point component - by - woven and have use of composite fibers of side-type, fixed to the fiber intersections soften or by thermally melting the low melting point component by thermocompression bonding The woven fabric on the inner surface of the stencil
A cylindrical plate cylinder for a stencil printing machine , wherein the cylinder is arranged so as to be in contact with the cylinder plate.